P2.231: A Rare Case of Recurrent Spontaneous Hemothorax Due to Intrathoracic Osteochondroma in a Pediatric Patient

Introduction: Osteochondromas are the most common benign bone tumors in the pediatric population, usually arising in the metaphyseal regions of long bones. Typically, osteochondromas affect pediatric and adolescent populations by presenting as an asymptomatic mass on incidental imaging. This report seeks to shed light on an atypical presentation of osteochondroma of the rib as a spontaneous hemothorax, contributing to the broader understanding of its clinical spectrum. The objective is to emphasize the importance of considering osteochondromas in differential diagnoses of spontaneous hemothorax to ensure timely and effective management.​

Case Description: An 18-year-old male with no significant past medical history presented to the ED with progressive rib and shoulder pain associated with pleuritic chest tightness and cough. The patient’s symptoms started 10 days prior with a syncopal episode while seated, leading to a diagnosis of pneumonia. He was treated with antibiotics and steroids. There was no report of trauma to the chest wall. Six days later, chest x-ray (CXR) demonstrated worsening effusion despite multiple antibiotic treatments. A CT thorax with contrast demonstrated a bony projection arising from the lower left rib extending in the region of the pleura which represented a small osteochondroma (Figure 1). A bedside thoracentesis drained 500mL of bloody fluid. According to light’s criteria the fluid was exudative. Fungal, bacterial, and acid-fast bacilli cultures were all negative. Fluid reaccumulated on repeat CXR four days later (Figure 2), suggesting recurrence of this patient’s spontaneous hemothorax. The patient remained hemodynamically stable without significant pain, cough, or dyspnea. A period of watchful waiting was favored over surgical intervention and the patient is currently receiving weekly CXR with Pulmonology. Determinations for definitive management are ongoing, as the risk of recurrence of his hemothorax is not well-understood.

Discussion: Osteochondromas have an incidence of 1 in 50,000 with a frequency rate of 1.5% in the western population. Seventy-five percent of the cases are identified in patients under the age of 20. Rib osteochondromas are often asymptomatic, but can cause mechanical irritation or direct injury to adjacent pleural structures, vasculature, or lung parenchyma when projecting inward toward the thoracic cavity. In this case, the recurrent spontaneous hemothorax is likely mechanical erosion or intermittent vascular injury caused by a portion of the rib osteochondroma abrading the parietal pleura or intercostal vessels. Literature review yielded similar reports of intrathoracic osteochondroma complicated by hemothorax. This is the first study to report a longitudinal course of re-accumulation.

Conclusion: This is the first study that reports a case of recurrent spontaneous hemothorax in the setting of intrathoracic osteochondroma. This case serves to enhance clinical awareness of a rare complication of osteochondroma and broadens the differential for expanding pleural effusion.